Aqueous explosive comprising higher amine,gelling agent and inorganic oxidizer salt

ABSTRACT

AN EXPLOSIVE COMPOSITION CONTAINING A SURFACTANT, A GELLING AGENT, AN AQUEOUS MEDIUM, AND AN OXIDIZER. THE SURFACTANT PROMOTES THE RAPID GELATION OF THE GELLING AGENT SO THAT THE GELLING PROCESS IS COMPLETE BEFORE THE COMCOMPONENTS OF THE COMPOSITION HAVE SEGREGATED.

United States Patent 95,947 AQUEOUS EXPLOSIVE COMPRISING HIGHER AMINE, GELLING AGENT AND INORGANIC OXIDIZER SALT Donald W. Edwards, Lehighton, Pa., assignor to Atlas Chemicals Industries, Inc., Wilmington, Del. N0 Drawing. Filed Jan. 22, 1970, Ser. No. 5,093

Int. Cl. C06b 19/04 US. Cl. 149-2 11 Claims ABSTRACT OF THE DISCLOSURE An explosive composition containing a surfactant, a gelling agent, an aqueous medium, and an oxidizer. The surfactant promotes the rapid gelation of the gelling agent so that the gelling process is complete before the components of the composition have segregated.

This invention relates to an explosive composition which rapidly gels.

PRIOR ART Slurry explosives generally contain a gelling agent such as guar gum to prevent the insoluble components of the explosive from segregating, leaving the explosive insensitive. These explosives are generally not pourable because they are too gelled; as such they are difiicult to handle and do not fill all the voids in a borehole which results in an inefficient explosive.

Since most gelling agents require time to gel, the commercial practice is to use excess gelling agent so that the gelation is complete enough at the end of the mixing stage to prevent segregation of the components. However, in addition to producing gels which are not pourable, this practice can also produce gels which are so tight that the Water is squeezed out leaving the explosive insensitive.

On the other hand, if less gelling agent is used, segregation may result, especially When the explosive is stored shortly after being manufactured at low temperatures which inhibit the gelling process. An explosive containing small amounts of gelling agent can sometimes be heated during the mixing stage in an attempt to ensure comple tion of the gelling process prior to storage. Normally, heat alone will not complete all of the crosslinking available from the conventional gelling agents present in the formulation. Thus, additional cross-linking takes place during storage with the possibility of ingredient separation clue to the incomplete initial gelation.

ADVANTAGES OF THE INVENTION I have discovered explosive compositions which gel rapidly and more completely during mixing and which can be made pourable. A more complete gelation during mixing permits the use of less gelling agent and helps prevent the formation of tight gels on storage, although sufficient gelling agent is used to prevent segregation on storage. In addition, these compositions generally have much better bag release that prior art compositions (bag release is the facility and completeness with which the explosive can be removed from a plastic bag), and the preferred compositions of this invention can be made pourable.

COMPOSITIONS The compositions of this invention contain a particular type of surfactant in addition to a gelling agent, an aqueous medium, and an oxidizer. A composition of this invention may be made from about 0.0025 to 0.1 p.b.w. (parts by weight) of the surfactant, about 0.0025 to 0.1 p.b.w. of a gelling agent, about 0.06 to 1.5 p.b.w. of an aqueous medium, and 1 p.b.w. of an oxidizer. Preferably, the compositions comprise about 0.0025 to 0.05 p.b.w. of the surfactant, about 0.005 to 0.05 p.b.w. of a gelling agent, about 0.125 to 1 p.b.w. of an aqueous medium, and 1 p.b.w. of an oxidizer. About 0.0001 to 0.05 p.b.w. of a gel promoter such as boric acid, borax, chromates, metal salts, etc., is preferably included to help promote gelation. In addition, the compositions preferably contain up to about 1.25 p.b.w. of a sensitizer and up to about 1.25 p.b.w. of a fuel in addition to other substances commonly used in explosives.

SURFACTANTS The surfactants of this invention are long-chain (i.e. at least about 8 carbon atoms) amines, preferably tertiary amines, which are soluble in a 50% ammonium nitrate solution. Examples of suitable surfactants include polyoxyethylene and polyoxypropylene alkyl amines, N-soya N-ethyl morpholinium ethosulphate, octyl dimethyl amine, decyl dimethyl amine, and octadecyl amine. The preferred surfactants are polyoxyethylene alkyl amines and N-soya N-ethyl morpholinium ethosulfate.

GELLING AGENT The gelling agent is a compound Which cross-links to gel the explosive composition. Suitable gelling agents include polysaccharides, such as galactomannans, and polyacrylamides; guar gum is preferred.

AQUEOUS MEDIUM The aqueous medium is preferably water, but up to about 50% of the Water may be substituted for With organic liquids such as ethylene glycol, formarnide, glycerine, etc.

OXIDIZER The oxidizer is a compound which is a source of oxygen during the explosion and is preferably an inorganic oxidizer salt, preferably ammonium nitrate. Other suitable oxidizers include sodium nitrate, calcium nitrate, magnesium nitrate, potassium nitrate, lithium nitrate, ammonium chlorate, potassium chlorate, sodium chlorate, ammonium perchlorate, potassium perchlorate, and 'sodium perchlorate.

SENSITIZER The sensitizer increases the detonability of the explosive. Suitable sensitizers include air bubbles and air-entrapping materials such as glass, urea-formaldehyde and phenol-formaldehyde resin spheres, bagasse, perlite, etc., explosive compounds such as TNT, DNT, tetryl, PETN, nitrostarch, smokeless powder, and alkyl amine nitrates such as methyl amine nitrate and ethylene diamine dinitrate, nitroparafiins such as nitromethane and nitropropane, and finely-divided metals such as aluminum and its alloys and magnesium and its alloys.

FUEL

The fuel consumes oxygen during the explosion; examples of suitable fuels include fuel oil, mineral oil, paraffin oil, bagasse, vegetable compounds, sulfur, coal, etc.; sulfur is preferred.

EXAMPLES The folowing examples illustrate this invention, and compare compositions within the scope of the invention with other compositions. The compositions listed in Column A of Table I below were formed by mixing together 200 gms. of a 60% ammonium nitrate solution and 2.8 gms. of a gelling agent. A second group of compositions were prepared in an identical manner except that 2 gms. of a surfactant was also added. Table I below gives the viscosity (cps) at room temperature using a Brookfield Viscometer and gives the pH of the compositions in Column A when fresh.

TABLE I B, viscosity A, viscosity (cps) (cps.

Gelling agent Fresh 1 day pH Fresh 1 day Polysaeeharide sold by Stein- Hall Co. under the trademark 705DA 9, 440 10, 080 l 5. l 9, 560 10, 320 Polysaccharide sold by Stein- Hall Co. under the trademark Polysaccharide sold by Stein- Hall Co. under the trademark 1212A 9, 280 10, 840 5. 1 9, 680 12, 640 Nonionic guar gum provided by Stein-Hall Co. under the 22, 560 24, 960 1 5. 1 23, 120 25, 520

trademark "Jaguar DE-1--- 26,480 29, 680 1 5. 1 27,280 30, 640

Modified guar gum provided by Stein-Hall 00. under the trademark "Jaguar EX-JB- 4, 080 5, 520 1 5. 1 4, 560 5, 920 Nonionic guar gum sold by Stein-Hall Co. under the 18, 320 20,160 1 5.1 23, 360 25, 440

trademark Jaguar 100" 10, 520 20,160 1 5.1 20,160 22,000

Modified guar gum sold by General Mills under the trademark Gendriv 570 1, 240 8, 360 l 5. 1, 480 12, 760

l 'olyoxyethylene octadecyl amine having an average of about 20 ethoxy groups per molecule sold by Atlas Chemical Industries, Inc., hereinafter referred to as polyoxyethylene (20) octadecyl'amlne.

2 Sodium lauryl sulfate sold by E. I. du Pont de Nemours and Company under the trademark Duponal C.

Table I shows that a surfactant of this invention, polyoxyethylene(20)octadecyl amine, significantly increased the viscosity of compositions using various gelling agents, while a surfactant not included within the scope of this invention, sodium lauryl sulfate, did not have a comparable effect on viscosity.

In another set of experiments, 200 gms. of a 60% ammonium nitrate solution and 2.8 gms. of a nonionic guar gum (Jaguar D*E-1) were mixed together to form control compositions. A second group of compositions were prepared in an identical manner except that 2 gms. of various surfactants were also mixed in. Table II below shows the increase in viscosity (cps) at room temperature, using a Brookfield viscometer, which resulted when various surfactants of this invention were used. Since pH has an effect on viscosity, the first group of compositions and corresponding control were prepared at a pH of 6.45 to 6.5 and another composition and control were prepared at a pH of 6 .15 to 6.2.

TABLE II Viscosity (cps) DH Surfactant Fresh 1 day fresh Octyl dimethyl amine sold by Baird Chemical Industries under the trademark Earlene 8S. 38, 840 50,000 6. 5 Decyl dimethyl amine sold by Baird Chemical Industries under the trademark Barlene 10S 28,480 70,000 6.45 Octadecyl amine sold by Armour Industrial Chemical Industries under the trademark "Armeen 18 32,000 49, 520 6.45 Control 28,840 46, 720 6. 5 35% solution of N-soya N -ethyl morpholenium ethosulphate sold by Atlas Chemical Industries, Inc., under the trademark G271 21, 080 24,160 6. 2 Control 20, 880 23, 840 6.15

TABLE III With pH Control surfactant Fresh 5. 2 8, 200 9, 200 9, 600 11, 000

In Table IV, compositions A to K were prepared by mixing the water, surfactant, and the nitrates and dinitrate at to 150 F. The pH was adjusted to 2 to 3 and the nitrostarch and TNT were added where used; after stirring the aluminum was added (composition G). A pre-mix containing the resin spheres, sulfur, and the gelling mixture was prepared and added with stirring. When the compositions began to thicken, the pH was adjusted with acetic acid to 3.5 to 4.5, and the ethylene glycol and nitromethane were added and stirred in for one minute where used. The pH was then adjusted with ammonium hydroxide to the final pH which instantly resulted in the formation of the gel. Whole ammonium nitrate prills were then stirred in, 15% (this percentage is included in the figure given in Table IV for ammonium nitrate) in cases B and C; 10% in case E; and 5% in cases H, J, and K.

Composition L was prepared by mixing the nitrates, dinitrate, and the water, heating to 160 F., and adjusting the pH to 4.0 with acetic acid. The air-entrapping spheres, sulfur, gelling mixture, and boric acid were blended and the heated nitrate solution was added incrementally while the temperature was maintained at F. The surfactant was added and the pH adjusted to 4.5 to 5.0 with sodium hydroxide solution. The nitromethane and ethylene glycol were mixed in and the pH was adjusted to the final pH with sodium hydroxide.

Composition M was prepared by mixing the sodium and ammonium nitrates and water at The pH was adjusted to 3 to 4 with acetic acid and the Jaguar 100 and boric acid were mixed in until thick. The airentrapping spheres, sulfur, and ethylene diamine dinitrate were mixed in and the pH adjusted to 4 with sodium hydroxide. The ethylene glycol and nitromethane were added and the final pH adjustment Was made with sodium hydroxide.

All of the compositions of Table IV were pourable, and most of the compositions (H, I, and K, for example) are pourable at low temperatures (20 to 30 F.); all the compositions had an oxygen balance between +10 and 30. The compositions were placed in 3" diameter plastic catridges and were detonated with a 3 x 6" 75% gelatin dynamite.

TABLE IV Composition (percent) of A B D E F G H I J K L M Air-entrapping spheres 'IIIIIIIIIIIIIIIII1""fd'""sff f' Ethylene-diamine dinitrate. 5. 0 10. 0 5. 0

Nitromethan Nitrostarch .NT Finalp Denslty,grams/cc- 1.47 1.46 1.44 1.40 1.26 1.28 nt 1.16 1.22 1.25 1.20 1.29 Velocity, t.p.s 16,200 12,195 11,900 17,090 16,340 16,025 17,045 14,285 17,095 17,360 17,360 17,010

I 41.7% boric acid, 49.2% guar gum, 9.2% guar gums sold by Stein, Hall & 00., Inc. in

'- Polyoxyethylene() octadecyl amine sold by Atlas Chemical Industries, Inc.

I Phenol formaldehyde in D, E, F, G, I, and J; glass in H, K, L, and M No'rE.nt Not tested.

I claim:

1. An explosive composition comprising a surfactant selected from the group consisting of polyoxyethylene and polyoxypropylene alkyl amines, N-soya N-ethyl morpholinium cthosulfate, octyl dimethyl amine, decyl dimethyl amine and octadecyl amine, a gelling agent, a sensitizer, an aqueous medium, and an inorganic oxidizer salt.

2. A composition of claim 1 containing a fuel.

3. A composition of claim 2 wherein the gelling agent is guar gum.

4. A composition of claim 3 wherein the sensitizer is nitromethane.

5. A composition of claim 4 containing an air-entrapping material.

6. An explosive composition comprising about 0.0025 to about 0.1 p.b.w. of a surfactant selected from the group consisting of polyoxyethylene and polyoxypropylene alkyl amines, N-soya N-ethyl morpholinium ethosulfate, octyl dimethyl amine, decyl dimethyl amine and octadecyl amine, about 0.0025 to about 0.1 p.b.w. of a gelling agent, about 0.06 to about 1.5 p.b.w. of an aqueous medium, up to about 1.25 p.b.w. of a fuel, up to about 1.25 p.b.w. of a sensitizer, and 1 p.b.w. of an inorganic oxidizer salt.

7. An explosive composition comprising about 0.0025 to about 0.1 p.b.w. of a surfactant selected from the group consisting of polyoxyethylene and polyoxypropylene alkyl amines, N-soya N-ethyl morpholinium ethosulfate, octyl dimethyl amine, decyl dimethyl amine and octadecyl amine, about 0.005 to 0.05 p.b.w. of a gelling agent, about 0.125 to 1 p.b.w. of an aqueous medium, 0.0001 to about 0.05 p.b.w. of a gel promoter, 1 p.b.w. of an inorganic oxidizer salt, up to about 1.25 p.b.w. of a sensitizer, and up to about 1.25 p.b.w. of a fuel.

8. A composition of claim 7 wherein the sensitizer is nitromethane.

9. The composition of claim 7 wherein said oxidizer is ammonium nitrate.

10. The composition of claim 9 wherein said gelling agent is guar gum.

11. The composition of claim 10 wherein said aqueous medium comprises water.

References Cited UNITED STATES PATENTS 3,397,097 8/1968 Atadan et a] 149-46 3,522,117 7/1970 Atadan et al. 149-46 X 3,419,444 12/1968 Minnick 149-2 LELAND A. SEBASTIAN, Primary Examiner U.S. Cl. X.R. 

